Fans of the new Fox medical drama Doc have officially met an entirely new Dr. TJ Coleman (Patrick Walker).

This week’s episode delved into the backstory between Dr. Amy Larsen and Dr. TJ Coleman, as well as a moment that Walker said changes the entire trajectory of his character’s life.

The evolution of Dr. TJ Coleman

“In a way, you almost watch him grow up, from being like a little kid doctor to a big boy doctor, in a way, because when we first meet him, he gets reprimanded within the first interaction he has with Amy,” Walker said in a recent interview with Blavity’s Shadow and Act before the finale. “You’re watching him essentially make a mistake, like the way that he goes about dealing with his patients, and she has to correct him on that.”

He added, “I mean, Episode 3, he almost kills the patient. So it’s like, very early on, we’re watching him make mistakes and then as we finish Episode 3, you kind of watch him get some courage and kind of earn his stripes as it pertains to the other doctors. … In Episode 4, you watch him go against the military and kind of watch him develop bravery through time, all the way until we get to these latter episodes. I feel like the evolution is very interesting. We’re watching him grow up within his first year of being a doctor.”

What is the big reveal that happened in Episode 9?

In the latest episode of Doc, viewers learn that TJ and Amy actually have a past — one in which she saves his life on a plane when he was a child, planting the seed that would ultimately bloom into him becoming a doctor himself.

“As an audience member, I think that the way we introduce how TJ and Amy know each other is brilliant. I like the fact that she saved his life on an airplane because he went scuba diving and then got on the plane the same or the next day — knowing about what that does to the body, I think that’s very interesting,” Walker said.

“I think it’s very interesting, and the main part of that being, knowing that this moment that she saved his life … he’s inspired by this woman enough to go and live his life differently beyond that moment,” he continued. “It’s actually similar to A Raisin in the Sun, the main character, she talks about watching this little boy fall down a hill and crack his head, and then the way that somebody was able to stitch up his head and save his life, like, how she was so moved by that. I was inspired by that with TJ, where he saw this woman save his life, and then he went into a life of service to save others on the battlefield and is now in a hospital. I think that revelation for myself, and the audience is really beautiful, and it all makes sense. It makes sense why he would be on Amy’s side. It makes sense why he will fight for her. It makes sense in Episode 1, when everybody was talking crazy about her, that he was the one to stand up to the people who were above him because ‘nobody’s gonna talk bad about the woman that saved my life and that inspired me to be a doctor.’”

How fans will get a peek inside Dr. TJ Coleman’s diary

Audiences only witnessed TJ in scrubs until the latest episode of Doc, something Walker said is significant in portraying his character as finally standing on his own two feet.

“The whole season he’s paired with other doctors. He’s supporting Amy. It’s very much like him aiding someone else,” Walker said. “So it feels like, in this episode, we get a chance to watch him as a civilian. He’s not on the clock. You get a chance to watch a young man, who has all this knowledge and who is not on the clock, trying to figure out how he’s going to save the life of his father — and going about it as a doctor, but also going about it purely as a son.”

He added, “Watching those parts of him where he’s just a son to a father that he loves. A big part of what we get in this episode, also, [is that] he doesn’t have to follow those same rules. He’s just a civilian. There’s nothing special about this moment. He can get a little rowdy just like everyone else can get a little rowdy. He can feel the emotions, just like everybody else feels emotions. Because, being a doctor, he can’t access those things on a day-to-day basis. So now it’s like, OK, when he looks at that monitor and he sees the thing that he thinks is cancer, he can actually take that in and really feel that. Because this is, number one, his father. Number two, there’s a bit more freedom because I got my Chuck Taylors and white button-up instead of having my white lab coat on.”

The Season 1 finale of Doc premieres on Tuesday, March 18, at 9 p.m. ET/PT on Fox.